Molding apparatus

ABSTRACT

An improved apparatus for molding thermosetting material, such as strips of uncured mill rubber or other thermosetting elastomers, includes a preheater assembly which preheats the thermosetting material to a temperature which is below its curing temperature. A movable pot receives at least a portion of a charge of the preheated strip material at a loading station. The pot is then moved to a discharge or unloading station where a ram assembly is extended to force the thermosetting material from the pot into a mold. The ram assembly is then retracted and the pot is returned to the loading station. The pot is then filled so as to contain a charge which includes both preheated strip material and thermosetting material which was not forced into the mold on the previous cycle of operation. The pot is cooled at the loading station to maintain thermosetting material in the pot at a temperature below its curing or setting temperature. As the pot is being loaded, a slide block applies pressure against the mold and heats the thermosetting material in the mold to a temperature above its setting temperature.

United States Patent 1 Taylor [111 3,748,075 1 July 24, 1973 MOLDINGAPPARATUS Don A. Taylor, 216 Mill St., Wadsworth, Ohio [22] Filed: July29,1971

[21] Appl. No.: 167,240

[76] inventor:

[52] U.S. Cl 425/251, 425/289 425/290, 425/298 [51] Int. Cl. B29c 1/00[58] Field of Search 425/242, 145, 244, 425/250, 251, 260, 289, 290,298, 299

[56] References Cited UNITED STATES PATENTS 2,883,704 4/1959 Jurgeleit425/251 3,674,391 7/1972 Welle 425/298 X Primary Examiner--H. A. Kilby,Jr. AttorneyYount and Tarolli s71 ABSTRACT An improved apparatus formolding thermosetting material, such as strips of uncured mill rubber orother thermosetting elastomers, includes a preheat'er assembly whichpreheats the thermosetting material to a temperature which is below itscuring temperature. A movable pot receives at least a portion of acharge of the preheated strip material at a loading station. The pot isthen moved toa discharge or unloading station where a ram assembly isextended to force the thermosetting material from the pot into a mold.The ram assembly is then retracted and the pot is returned to theloading station. The pot is then filled so as to contain a charge whichincludes both preheated strip material and thermosetting material whichwas not forced into the mold on the previous cycle of operation. The potis cooled at the loading station to maintain thermosetting material inthe pot at a temperature below its curing or'setting temperature. As thepot is being loaded, a slide block applies pressure against'the' moldand heats the thermosetting material in the mold-to a temperature aboveits setting temperature.

38 Claims, 14 Drawing Figures 7 Sheets-Sheet 2 Pmmcd July 24, 1973Patented July 24, 1973 7 Sheets-Sheet 5 00 A "@15 3; 5} ATTORNEYSPatented July 24, 1973 7 Sheets-Sheet 6 O O O O O O O O O O O 0 O O O OO O O o O O O 0 O O O 0 O O O O O OO O O O //VVE/V7 0A DON A. Z JYLOR r,M W Mf ATTOPAEMS' v QQN Patented July 24, 1973 TSheets-Sheet 7 E N mmMOLDING APPARATUS The present invention relates to an improved apparatusand method for forming articles of a thermosetting material.

There are three types of molding machines which are in frequentcommercial use, namely a compression press or machine, a transfer pressor machine, and an injection press or machine. When rubber or plasticarticles are made with a compression press, non-cured blanks formed of apredetermined volume of thermosetting material are loaded into cavitiesin a mold which is then subjected to heat and pressure for a timesufficient to set, i.e., cure, the thermosetting material. This moldingmethod has a number of advantages, including relatively low cost of thepress and molds and a high level of efficiency and dependability sincethe press is non-automated. The drawbacks of the compression moldingprocess include relativelyhigh labor operating costs, long cure periods,and a relatively high material waste factor.

Transfer molding machines or presses have the advantage that parts canbe molded with relatively little flash material. This is possible due tothe fact that the .moldsin the press can be clamped tightly togetherbefore the transfer of material into the mold. Another advantage of thetransfer molding press or machine is that it has a relatively low laborcost in that a blank of thermosetting material can be loaded into a potinstead of being precut and manually placed in a mold cavity as is thecase with a compression molding press. However, transfer molding hassubstantial disadvantages in that there are relatively high labor costsinvolved in the preparation of the blanks of raw material for the press.

In addition, there is a relatively high material waste or scrap factordue to the fact that the material is relatively cold when it isintroduced into a relatively hot mold cavity'wh'ich may resultin'premature curing or setting of a skin surface. Another disadvantageof transfer molding is that the required cure period is relativelylon'gdue to the fact that the thermosetting material is introduced intothe mold at a relatively low temperature.

injection molding machines differ from compression and transfer moldingpresses in that the material is preheated and injected under highpressure into a mold cavity. This enables injection molding machines toovercome many of the disadvantages associated with compression andtransfer molding. However, injection molding machines have a relativelylarge waste or scrap factor due to a curing of material in anon-reuseable runnersystem. Another disadvantage of the injectionmolding machines is the inability, for certain articles at least, todesign a runner and gate system that will efficiently feed the moldcavity ina uniform manner. Another disadvantage of injectionmoldingmachines is the limit on material capacity which can be injectedon an operating cycle due to the poor ability of rubber and otherthermosetting materials to absorb or conduct heat necessitating theprovision of a relatively large reserve of preheated material which maycure prematurely.

Accordingly, it is an object of this invention to provide anew andimproved apparatus and method for molding-elastomeric materials whichprovide the advantages of compression, transfer, and injection typemolding machines without the disadvantages which are associated withthese machines and, more specifically,

to provide molding apparatus and method which with a minimum of wastecan utilize relatively low cost raw material which has not beenpre-processed or formed into blanks and which include the use of arelatively inexpensive mold which does not have a complicated runner andgate feeding arrangement.

Another object of this invention is to provide a new and improvedapparatus for molding thermosetting material where the apparatus isrelatively simple in construction and lends itself to repetitive qualityoperation with a minimum of supervision and waste.

Another object of this invention is to provide a new and improvedapparatus for forming molded articles from strip material wherein theapparatus includes a preheater assemblyfor preheating the stripmaterial, a pot for receiving a charge of the preheated strip material,and a ram or similar means for pressurizing a charge in the pot to forceat least a portion of thecharge to flow from the pot into the mold.

Another object of this invention is to provide a new and improvedapparatus for molding a thermosetting material and wherein the apparatusincludes a mold assembly formed by a plurality of relatively movableparts and having an entrance opening to a mold cavity, a movable pot forholding-a charge of the thermosetting material, an assembly for movingthis pot between a loading position and an unloading position on whichthe pot is effective to retain the parts of the mold assembly againstmovement and material can beforced from the pot into the mold cavity,wherein a device is provided for applying heat and pressure to the moldassembly upon movement of the pot from the unloading position to theloading position to retain the parts of the mold assembly againstmovement relative to each other and to promote a setting, i.e., curing,of the thermosetting material in the mold assembly.

Another object of this invention is to provide a cyclically operableapparatus for forming molded articles from a thermosetting material andwherein the apparatus includes a pot for holding a charge of thethermosetting material, a loader assembly for loading at least a portionof a charge of the thermosetting materialinto the pot during eachoperating cycle of the apparatus, and a control assembly for detectingwhen the portion of a charge remaining in the pot at the end of'onecycle of operation of the apparatus and the thermosetting material addedto the pot during a next succeeding cycle of operation of the apparatusequals a charge of a predetermined magnitudeand for interruptingoperation of the loader assembly in response to the detecting of acharge of the predetermined magnitude inthe pot.

Another object of this invention is to provide a new and improvedapparatus for use in molding thermosetting material and wherein theapparatus includes a pot for holding a charge of the thermosettingmaterial and a cooling assembly at a pot loading station for maintainingthermosetting material in the pot at a'temperature below the settingtemperature of the thermosetting material.

Another object of this invention is to provide'anew and'improvedmethod-of fomiing molded articles from thermosetting strip materialwherein the method includes the steps of providing a strip ofthermosetting material, preheating at least a portion of the strip ofthermosetting material to a temperature belowits-setting temperature,loading a charge of the preheated thermosetting strip material into apot, andfo'rcing at least a portion of this charge to flow from the potinto a mold.

Another object of this invention is to provide a new and improved methodof molding thermosetting material and wherein the method includes thesteps of providing a mold assembly, providing a pot which is movablebetween a loading position at which the thermosetting material is placedinto the pot and an unloading position at which the thermosettingmaterial is forced to flow from the pot into the mold assembly andwherein pressure is applied to the mold assembly after movement of thepot to the loading position.

Another object of this invention is to provide a new and improved methodfor molding thermosetting material during a plurality of operatingcycles wherein the method includes the steps of providing a pot, loadingthe pot with at least a portion of a predetermined charge of thethermosetting material during each of a plurality of operating cycles,forcing a portion of the predetermined charge of the thermosettingmaterial to flow into the mold and retaining another portion of thepredetermined charge in the pot during each of the plurality ofoperating cycles, detecting during a loading of a pot when the retainedportion of a charge remaining in the pot at the end of one of theoperating cycles and the thermosetting material added to the pot duringthe loading of the pot on the next succeeding operating cycle equals thecharge of predetermined magnitude, and interrupting the loading of thepot during each of the operating cycles upon detection of a charge ofthe predetermined magnitude in the pot.

These and other objects and features of the invention will become moreapparent upon a consideration of the following description taken inconnection with the accompanying drawings, wherein:

FIG. 1 is a partially broken away schematic illustration of a moldingapparatus constructed in accordance with the present invention;

FIG. 2 is a fragmentary schematic illustration taken generally along theline 2-2 of FIG. 1 and further illustrating the construction of themolding apparatus;

FIG. 3 is an enlarged fragmentary sectional view, taken generally alongthe line 33 of FIG/2, illustrating the construction of a preheaterassembly for preheating strip material;

FIG. 4 is a fragmentary plan view, taken generally along the line 4-4 ofFIG. 1, further illustrating the construction of the preheater assembly;

FIG. 5 is an enlarged fragmentary schematic elevational view, takengenerally along the line 55 of FIG. 2, illustrating the relationshipbetween a movable pot, loading assembly, mold, slide block for heatingand applying pressure to the mold, and fixed and movable rams of themolding apparatus of FIG. 1;

FIG. 6 is a fragmentary schematic elevational view, similar to FIG. 5,of the loading of strip material into the pot by the loading assembly asthe pot is cooled;

FIG. 7 is a fragmentary schematic elevational view.

depicting the forcing of material from the pot into the mold;

FIG. 8 is a schematic fragmentary elevational view, similar to FIG. 7,depicting the pot after a major portion of a charge has been forced fromthe pot and a minor portion of a charge remains in the pot;

FIG. 9 is a fragmentary plan view, taken generally along the line 9-9 ofFIG. 1, illustrating the arrangement of a plurality of dischargeopenings in the bottom of the pot;

FIG. 10 is an enlarged fragmentary schematic view illustrating theforcing of material through the discharge openings in the pot and intothe mold;

FIG. 11 is a schematic fragmentary elevational view, depicting movementof the pot from the unloading po sition of FIGS. 7 and 8 toward theloading position of FIG. 5 with a minor or remaining portion of a chargein the pot;

FIG. 12 is an enlarged fragmentary view, generally similar to FIG. 10,illustrating the relationship between the mold and the pot upon initialmovement of the pot toward the loading position;

FIG. 13 is a schematic elevational view, generally similar to FIGS. 5and 11, depicting the application of heat and pressure to the mold bythe slide block during loading of the pot; and

FIG. 14 (on sheet two of the drawings) is a schematic sectional view,taken generally along the line I4 14 of FIG. 1, illustrating therelationship between a guide rail and the slide block.

Although a molding apparatus 20 constructed in accordance with thepresent invention can be utilized to mold many different types ofmaterials, it is illustrated in FIG. 1 in association with athermosetting strip material 22 which is supplied from a suitablecontainer 24. The thermosetting strip material 22 is preheated to atemperature which is below its setting, i.e., curing, temperature in apreheater assembly 28 (see FIGS. 1-4). The preheated strip material isthen conducted to a loading station 30 where a loader assembly 32 loadsthe strip material into a movable pot 34 (FIGS. 5 and 6).

When the movable pot 34 has been filled so as to contain a predeterminedcharge of the thermosetting material 22, the pot 34 is shifted from theloading station 30 to an unloading or discharge station 38 where the potoverlies a mold 40 disposed on a movable ram 42 (FIG. 1 The movable ram42 and mold 40 are then raised so that a fixed ram 46 telescopicallyenters the pot 34 (FIG. 7) to force a major portion of the thermosettingmaterial in the pot 34 into the mold 40. The movable ram 42 is thenretracted (FIG. 8) and the pot 34 is shifted from the loading station 38to the unloading station 30 (FIG. 11) with a minor portion 50 of thethermosetting material remaining in the pot 34 to form an initialportion of a charge for a next succeeding cycle of operation of themolding apparatus 20.

After the pot 34 has returned to the loading station 30, the movable ram42 is again raised to press a horizontally extending bottom surface 56of a slide block 58 and pot 34 against the mold 40 (FIG. 13). Thispressure holds upper and lower sections 62 and 64 of the mold tightlytogether so that the thermosetting material 22 does not leak out betweenthe relatively movable sections of the mold. As the mold sections 62 and64 are pressed together by the slide block 58 and the next succeedingcharge of the thermosetting material is loaded into the pot 34, thethermosetting material in the mold sets. The curing of the material inthe mold 40 is promoted by heater elements 74 disposed in passages 76 inthe slide block 58. Since the pct 34 is also formed in the slide block58, a cooling block or element 80 is provided at the loading station 30to prevent the minor portion of the previous charge remaining in the pot34 from being heated to a temperature above its setting temperature asadditional thermosetting material is loaded into the pot.

Although it is contemplated that'the molding apparatus will be utilizedto mold articles from strips of many different types of syntheticelastomers which are advantageously set with the application of heat,the molding apparatus 20 is advantageously utilized to mold articlesfrom a strip 22 of uncured mill rubber. It should be noted that thestrip 22 of raw mill'rubber is utilized without being formed into blanksof a predetermined size, as is commonly done for compression andtransfer molding, or being formed into a cylinder or pellets, as isoften done for extrusion molding. Of course, this lack of processing ofthe strip rubber 22 before it is supplied to the molding apparatus 20substan tially reduces the material cost for the articles molded by theapparatus.

To reduce the curing time required to set the articles molded from thestrip material 22 to their permanent configuration in the mold 40, thestrip material 22 is heated to a temperature which is slightly below itssetting (i.e., curing) temperature in the preheater assembly 28. Topromote a rapid heating of the strip material 22 so that adequatematerial is available to provide a relatively large charge for immediateloading into the pot 34 during successive cycles of operation of themolding apparatus 20, the preheater 'assembly28 includes a pair ofheating platens 82 and 84 (FIG. 3). The platens 82 and 84 are pressedagainst opposite'sides'86 and 88 of the strip material 22 under theinfluence of piston and cylinder assemblies 90 (see FIGS. 1 and '2).Thus, the heater platen 84 is connected with piston rods 94 (see FIGS. 3'and-4) and is movable toward and away from the fixed heater platen'82by'the piston and cylinder assemblies 90.

When a portion of the elastomeric strip material '22 tobe heated isdisposed between the platens 82 and 84 (as shown in FIG. 3), the pistonand cylinder assemblies 90 are activated to press the-platen84 towardthe platen 82. This results in a firm pressure contact between heatingsurfaces 98 and 100 (FIG. 3) of the platens82 and 84 and the oppositesurfaces 86 and 88 of the stri'pmaterial 22 to promote the conduction ofheat from the platens to the strip material. Heater cores 104 and 106are provided in the platens 82 and 84. While it is contemplated thatmany different types of heating apparatus could be used, in theembodiment of the invention illustrated in FIG. 3, the cores 104 and 106include electrical heating strips 110 and 112.

Once a length of strip material 22 disposed between the heater surfaces98 and 100 of the platens 82 and 84 has been preheated to the desiredtemperature, the piston and cylinder assemblies 90 are deactivated torelease the pressure applied to the strip material. Conveyor chains 116and 118 on the platens 82 and '84 are then driven by sprockets 122 tomove pivotally interconnected links 124 of the conveyor chains andfeedthe heated portion of the strip material 22 to a storage loop 130 (FIG.1). The preheated strip material remains in the storage loop 130 untilit is fed by rollers 132 and 134 to the loader assembly 32 as requiredduring the loading of the pot 34. To maintain the material in thestorage loop 130 at its preheated temperature, walls 138 (see FIG. 3) ofthe preheater assembly 28 are insulated so that the interior of thehousing is at substantially the preheat temperature. The conveyor chains116 and 118 are driven by a motor 142 (FIG.-4)

which is connected with a feed roll 144 which is in turn connected withthe sprockets 122 for the conveyors .1 l6'and 118 by a chain 148.Although the platens 82 and-84 include conveyor chains 116 and 118having links with flat hard surfaces which apply pressure against bothsides of the strip material 22, it should be understood that other typesof heating and conveying devices could be provided in the preheaterassembly 28 if desired.

A charge comprising a predetermined volume of the strip material 22 isaccumulated in the pot 34 during each cycle of operation of the moldingapparatus 20. This charge includes the minor portion 50 (see FIG. 11) ofthe charge remaining in the pot from the last cycle of operation of themolding apparatus 20 and preheated strip'material 22 added during thepresent cycle of operation of the molding apparatus. Thus, at thebeginning of each cycle of operation of the molding apparatus 20, thepot 34 is returned to the loading station 30 with the remaining portion50 of the last charge in the pot 34. A sufficient quantity of thestrip'material 22 is then deposited in the pot 34 by operation of theloader assembly 32 to accumulate a charge of a predetermined magnitude.

In the illustrated embodiment of the invention, the loader assembly 32'includes a movable ram (see FIG. 5) which is extended telescopicallyinto the pot 34 with a length of the strip material 22 overlying the pot34 (FIG. 6). As the movable ram 160 enters thepot 34, the portion of thestrip material 22 overlying the pot is severed and compressed into theother material in the pot. The ram 160 is then withdrawn from the potand the strip material 22is advanced by the feed rollers 132 and 134 sothat-a next succeeding portion of the strip material overlies the pot.The movable ram 160 is'then lowered into the 'pot'to again sever the endportion of the strip material 22 and compress the severed end portioninto the material'previously deposited in the pot 34. It should be notedthat the pressure with which the movable ram compresses the material inthe 'pot 34 is sufficient to cause the strip material to flow againstside surfaces of the pot so that the pot is completely filled ahead 'ofthe ram 160 when it is in the lowerecl position of FIG. 6. v

When the minor portion of. the material remaining in the pot 34 from thepreceeding cycle of operation of the molding apparatus 20 and the stripmaterial depositied in the pot by operation of the loader assembly 32during the present cycle of operation of the molding apparatus20 isequal to a charge of a predetermined magnitude, an actuator member 166on the ram 160 will not be moved downwardly past an actuator 168 for alimit switch 170 to signal a suitable control circuit that the desiredcharge has been accumulated in the pot 34. Although the limit switch 170has been shown schematically in FIG. 5 and 6, it should be understoodthat the limit switch .could be activated by the accumulation of apredetermined amount of material in the pot 34 or by movement of a drivepiston for the ram 160. In any case, the position of the switch actuator168 is adjustable to enable charges of different sizesto be accumulatedin the pct 34 and articles of different sizes to be molded.

If the minor or remaining portion 50 of the previous charge is heated toa temperature above its curing temperature for a substantial period oftime, or is scorched, this material cannot be used on the nextsucceeding cycle of operation of the molding apparatus 20 and is wasted.This remaining or minor portion 50 of the preceeding charge may beheated excessively by being momentarily exposed to a relatively hightemperature while the major portion of the previous charge is beingforced into the mold 40. The remaining or minor portion 50 of the chargecould be heated excessively under the influence of heat transferred fromthe heating element 74 in the slide block 58 as the material in the mold40 is cured and the pot 34 is loaded. Accordingly, the bottom surface 56of the pot 34 rests on the cooling element or block 80 having coils 172through which a suitable refrigerant is circulated (see FIGS. and 6). Byusing the cooling element 80, a substantial reduction in waste materialis achieved over a known molding device.

While it is important to provide the cooling element or block 80 toprevent the material in the pot 34 from being overheated, it is alsodesirable to maintain the material in the pot at a temperature closelyapproximating the preheat temperature. Accordingly, auxiliary heaters174 and 176 are proviced in the slide block 58 to maintain the materialin the pot 34 at substantially the preheat temperature. Suitable sensingdevices are associated with the auxiliary heaters 174 and 176 and thecooling element 80 to detect the temperature of the material in the potand regulate the operation of the cooling element and auxiliary heatersso that the material is neither cooled to too low a temperature orheated to too high a temperature.

After a charge of a predetermined magnitude has been loaded into the pot34 and the articles molded on the previous cycle of operation have beenremoved from the mold 40, the pot is shifted from the loading station 30to the unloading station 38. At the unloading station 38, dischargeopenings 184 in a bottom plate 186 (see FIG. 9) of the pot 34 arealigned with entrance passages or sprews 190 leading to mold cavities192 (FIG. 10). Since the discharge openings 184 in the bottom plate 186of the pot 34 are aligned with the entrance passages 190 to the moldcavities 192, a major portion of the charge in the pot 34 can be forcedthrough the discharge openings and entrance passages into the moldcavities when the lower ram 42 is raised and the fixed ram 46 enters thepot 34 (see FIGS. 7 and 10). The bottom plate 186 is removable to enablea bottom plate (not shown) having a different number and arrangement ofdischarge openings to be substituted for the bottom plate 186. Thisenables existing molds having sprue passage arrangements which aredifferent from that of the mold 40 to be utilized.

After the major portion of the charge in the pot 34 has been forcedthrough the discharge openings 184 into the mold 40, the movable ram 42is lowered so that the slide block 58 is clear of the fixed ram 46 (seeFIG. 8). The slide block 58 is then moved to the right (as viewed inFIG. 8) through the intermediate position of FIG. 11 to the loadingposition of FIG. 13 with the minor portion 50 of the charge remaining inthe pot 34. Upon initial movement of the pot 34 toward the loadingposition, thermosetting material extending between the mold passages 190and the discharge openings 184 is severed in the manner illustrated inFIG. 12. As the bottom 56 of the pot 34 is moved relative to the mold40, the passages 190 to the mold cavities 192 are sealed by the bottomsurface 56 of the slide block 58 (FIG. 5) which moves over the mold 40.

During movement of the pot 34 toward the loading station 30, a scraperblade 198 (see FIG. 11) engages the bottom surface 56 of the slide blockand scrapes any material protruding out of the passages 184 from thebottom of the slide block 58. If desired, a movable knife blade could beprovided between the slide block 58 and the mold 40 to sever thematerial extending from the pot discharge passages 184 to the moldpassages 190. Of course, this knife blade would scrape away any materialadhering to the bottom of the slide block 58. v

The slide block 58 may be moved relative to the loading and unloadingstations 30 and 38 by means of a mechanically actuated piston andcylinder assembly 204 (see FIGS. 1 and 2). When the piston and cylinderassembly 204 is retracted, a piston rod 206 (FIG. 2) moves the slideblock 58 toward the left (as viewed in FIG. 2) to move the pot 34 fromthe loading position to the unloading position. This movement of theslide block 58 is guided by a pair of parallel rails 208 and 210 whichare disposed on opposite sides of the molding machine (see FIG. 2) andextend for substantially the entire length of the molding machine. Tooperatively interconnect the guide rail 210 and slide block 58, a plate214 (FIG. 14) mounted on the guide rail extends into a groove 216 formedin the slide block 58. Of course, the guide rail 208 is connected withthe slide block 58 in a similar manner.

When the movable ram 42 and mold 40 are raised, the slide block 58 andpot 34 are also raised (see FIGS. 11 and 13). To enable the slide block58 to move upwardly with the movable ram 42, the guide rails 208 and 210are movably connected with a fixed frame 220 (FIG. 1) of the moldingapparatus 20 by vertical support bars 222 which are slidably received insleeves 224 connected to the frame. Therefore, upon upward movement ofthe movable ram 42, the support bars 222 slide upwardly relative to thesleeves 224. Adjustable stop nuts 226 are connected with the supportbars 222 to limit the downward movement of the guard rails 208 and 210upon retraction of the movable ram 42. To maintain the bottom surface 58of the pct 34 in contact with the cooling block while pressure is beingapplied to the mold 40 by slide block 58, the cooling block extendsbetween and is connected to the guide rails 208 and 210.

Once the thermosetting material in the mold cavities 192 and passageshas set, the excess material remaining in the mold passages 190 must bestripped awayfrom the article in the mold cavity. To facilitate removingthis excess material, a pair of plates 230 and 232 (see FIG. 10) areprovided between the upper mold section 62 and the slide block 58. Theplate 230 is hingedly connected with the plate 232 so that it can beraised and moved away from the plate 232 after the mold 40 has beenmoved out from under the slide block 58. Upon raising the plate 230,sprue material 236 in the passages 190 is readily accessible and can beremoved from the lower plate 232 by pulling upwardly on a thin sheet 240of flash material which extends between the sprews associated with theopenings 190 to the mold cavities 192.

To'minimize waste material, the plates 220 and 232 limit the formationof the flash sheet 240 to a relatively small predetermined thickness. Byproviding a predetermined thickness and extent of the flash sheet 240,the waste material in the flash can be minimized while still providingsufficient strength to enable the sprew material 236 to be stripped fromthe mold 40. To pro vide fora flash sheet of a predetermined thickness,a flat thin cavity 244 is formed between parallel surfaces 246 and 248of the plates 230 and 232. These surfaces form the flash 240 of the samethickness and extent during each molding operation so that the amount offlash and waste material can be minimized while still providingsufficient flash to enable the sprue material 236 to be stripped fromthe mold.

Under certain operating conditions it is contemplated that tlie mold 40will be moved transversely outwardly from between the fixed and movablerams 42 and 46. However, under other operating conditions it iscontemplated that it may be; desirable to lower the movable ram 42 tosuch an extent that the mold 40 can be opened while remaining on themovable ram. If the mold 40 is to be opened while remaining on themovable ram 42, a relatively large clearance must be provided betweenthe mold 40'and the slide block 58 when the movable ram 42 is fullyretracted. To provide for this relatively large clearance, the frame 120includes a support section 250 (see FIG. 1) which is movable from theoperating position shown in solid lines in FIG. 1 to the operatingposition shown in dashed lines in FIG. 1. The fixed ram 46 is secured tothe frame section 250 so that upon movement of'the frame section to thedashed line position of FIG. 1, a relatively large clearance is providedbetween the fixed ram 46 andmovable ram 42. To enable the frame section250 to be moved to the dashed line position, the frame section isconnected to support columns or posts 254 having threaded upper endportions by means of releasable lower clamp sections (not shown) andnuts 256. Of course, if the frame section 250 could be releasablyconnected to the support post 254 in any desired manner.

From the foregoing description, it can be seen that the moldingapparatus 20 combines the'advantages of compression, transfer andinjection type molding without the disadvantages which are frequentlyassociated with these machines. Thus, elastomeric strip material 22,such as rubber, can be molded in relatively inexpensive molds with aminimum of waste without the provision of a relatively complicated sprueand. gate arrangement which is difficult to feed. The molding apparatus20 can be operated at a relatively high speed since the strip material22is quickly heated inthe preheater 28 and transferred to the pot 34 whilematerial which was forced'into the mold 40 on the previous cycle ofoperation is being cured. To minimize waste material, a relatively smallor minor portion 50 0f achargefrom one cycle of operation formsa part ofthe charge for the next cycle of operation of the molding apparatus. Toprevent this remaining material from being overheated, a cooling block80 cools the pot 34 while it is being loaded with preheated'stripmaterial by operation of the lower assembly 32. The minimization ofwaste is also promoted by-the mold assembly 40which includes plates 230and 232 for providing flash240 of a prede- -termined thickness on eachcycle of operation of the moldingeapparatus. Relatively high speedeconomic operations of the molding apparatus isalso promoted by theslide block 58 which. applies heat and pressure to the mold 40 while thepot 34' is being. charged with the preheated strip material 22.

Having described a specific preferred embodiment of the invention, thefollowing is claimed:

. 1. An apparatus for forming moldedv articles from an elongated stripof material, said apparatus comprising preheater means for preheating atleast a portion of the elongated strip of material, pot means spacedfrom said preheater for receiving a charge of preheated strip materialfrom said preheater means, said pot means having at least one dischargeopening through which preheated material may pass from said pot meansinto a mold, means for loading at least a portion of a charge ofpreheated strip material from said preheater means into said pot means,and means spaced from said preheater means for pressurizing a charge ofpreheated material in said pot means to force at least a portion of thecharge of preheated material to flow from said pot means through saiddischarge opening into the mold.

2. An apparatus as set forth in-claim 1 wherein said preheater meansincludes means for heating at least a portion of an elongated strip ofmaterial, said-means for loading a charge of preheated strip materialinto said pot means including means for severing a preheated end portionfrom the strip of material and for loading the severed end portion intosaid potmeans.

3. An apparatus as set forth in claim 1 wherein said pot means includeswall means for defining a cavity for holding a charge of preheated stripmeterial, said means for loading a charge of preheated strip materialinto said pot means including feed means for positioning a preheated endportion of the strip of material across said cavity, piston meanscooperable with said wall means to sever. the preheated end portion fromthe strip of material, and means for effecting relative movement betweensaidwall means and piston means to sever thepreheated end portion fromthe strip of material.

4. An apparatus as set forth in claim 1 wherein said preheater meansincludes a pu'rality of flat elongated surfaces, heater means forheating said surfaces, and means for pressing said surfaces againstopposite sides of a portion of thestrip of material to heat the portionof the strip of material engaged by said surfaces.

.5. An apparatus as set forth in claim 4 wherein said preheater meansfurther includes means for moving the heated portionof the strip ofmaterial from said preheater means to said means for loading a charge ofpreheated strip material into said pot means.

' 6. An apparatus as set forth in claim 5 wherein said means for movingthe heated portion of the strip of material includes drive means formoving said surfaces relative to said means for loading a charge ofpreheated strip material into said pot means.

7. An apparatus for forming molded articles from strip material, saidapparatus comprising preheater means for preheating the strip material,pot means for receiving a charge of preheated strip material, said potmeans having at least one discharge opening through which preheatedmaterial may pass from said pot means into a mold, means for loading atleast a portion of acharge of a preheated strip material from saidpreheater means into said pot means, means for pressurizing a charge ofpreheated material in said pot means to force at least a portion of thecharge of preheated material to flow from said pot means through saiddischarge opening into the mold, and means for moving said pot meansbetween a loading station at which the discharge opening in said potmeans is spaced from an entrance opening to the mold and an unloadingstation at which the discharge opening in said pot means is disposedadjacent to the entrance opening to the mold, said means for loading acharge of preheated strip material from said preheater means into saidpot means being located at said loading station, said means forpressurizing a charge of strip material in said pot means being locatedat said unloading station.

8. An apparatus as set forth in claim 7 wherein said pot means includeswall means defining an open cavity, said means for pressurizing a chargeof strip material in said pot means including ram means which isdisposed in axial alignment with said cavity when said pot means is atthe unloading station and means for effecting relative movement betweensaid ram means and said pot means to extrude at least a portion of thecharge of preheated strip material from said pot means to the mold, saidmeans for moving said pot means between the loading and unloadingstations including piston and cylinder means operatively connected withsaid pot means and means for effecting operation of said piston andcylinder means to move said pot means between the loading station inwhich the open cavity in said pot vmeans is offset to one side of saidram means and the unloading station at which the open cavity in said potmeans in disposed in axial alignment with said ram means.

' 9. An apparatus as set forth in claim 7 further including movableheater means for applying heat to material in the mold, said means formoving said pot means between the loading and unloading stationsincluding means for moving said heater means from an inactive positiondisposed to one side of the mold to the unloading station simultaneouslywith movement of said pot means from the unloading station to theloading station to enable said heater means to heat material in the moldwhile a charge of material is loaded into said pot means at the loadingstation.

10. An apparatus as set forth in claim 9 further including cooling meansfor maintaining the temperature of material in said pot means below apredetermined temperature during heating of the material in the mold bysaid heater means.

11. An apparatus as set forth in claim 7 further including retainermeans for applying pressure to the mold, said means for moving said potmeans between the loading and unloading stations including means formoving said retainer means from an inactive position disposed to oneside of the mold to the unloading station simultaneously with movementof said pot means from the unloading station to the loading station.

12. An apparatus as set forth in claim 11 further including heater meansfor applying heat to the material in the mold, said heater means beingmounted on said retainer means for movement therewith from the inactiveposition to the unloading station simultaneously with movement of saidpot means from the unloading station to the loading station to enablesaid heater means to heat material in the mold while said retainer meansapplies pressure to the mold.

13. An apparatus for use in molding a material, said apparatuscomprising a mold assembly defining an entrance opening to a moldcavity, said mold assembly including a plurality of relatively movableparts, movable pot means for holding a charge of the material, said potmeans having at least one discharge opening through which the materialmay pass from said pot means to the entrance opening to the mold cavity,means for moving said pot means between a loading position in which thedischarge opening is spaced from the entrance opening to the mold cavityand an unloading position in which the discharge opening is adjacent tothe entrance opening to the mold cavity, said pot means being effectiveat the unloading position to apply pressure to said mold assembly toretain the parts of said mold assembly against movement relative to eachother, means for forcing at least a portion of a charge of material fromsaid pot means into the cavity in said mold assembly when said pot meansis at the unloading position, and means for applying pressure to saidmold assembly after movement of said pot means from the unloadingposition to the loading position to retain the parts of said moldassembly against movement relative to each other during a setting ofmaterial in said mold assembly.

14. An apparatus as set forth in claim 13 wherein the material is athermosetting material and wherein the apparatus further includes meansfor applying heat to the thermosetting material in the mold cavity whensaid pot means is at the loading position.

15. An apparatus as set forth in claim 14 further including preheatermeans for preheating a charge of the thermosetting material prior toloading of the charge of thermosetting material into said pot means.

16. An apparatus as set forth in claim 15 further including coolingmeans for maintaining any material remaining in said pot means at atemperature below the setting temperature of the material when said potmeans is at the loading position.

17. An apparatus as set forth in claim 15 wherein said preheater meansincludes strip conveyor means for moving and heating a strip of thethermosetting material, said apparatus further including means forsevering an end portion from a heated strip of the thermosettingmaterial and loading the severed end portion into said pot means whensaid pot is at the loading position.

18. An apparatus as set forth in claim 13 wherein said mold assemblyincludes flash limiting means for limiting the formation of flash as thematerial is forced from said pot means into the mold cavity.

19. An apparatus as set forth in claim 13 wherein said pot means andsaid means for applying pressure to said mold assembly areinterconnected and define a surface means which is maintained incontinuous engagement with said mold assembly upon movement of said potmeans from the unloading position to the loading position.

20. An apparatus as set forth in claim 13 wherein said pot meansincludes a surface which is disposed in pressure engagement with saidmold assembly when said pot means is in the unloading position, saidsurface of said pot means defining the discharge opening through whichthe material passes from said pot means into the mold assembly, saidmeans for applying pressure to said mold assembly including a pressureelement having a surface which forms a continuation of said surface ofsaid pot means, said means for moving said pot means between saidloading and unloading positions being effective to move said surface ofsaid pressure element into engagement with said mold assembly and tosimultaneously therewith move said surface of said pot means out ofengagement with said mold assembly as said pot means moves from saidunloading position to said loading position.

21. An apparatus for use in molding thermosetting material, saidapparatus comprising movable pot means for holding a charge of thethermosetting materiaL said pot means having at least one dischargeopening through which the thermosetting material may pass from said potmeans into a mold, means for moving said pot means between a loadingposition at which the discharge opening in said pot means is spaced froman entrance opening to the mold and an unloading position at which thedischarge opening in said pot means is adjacent to the entrance openingto the mold, means for forcing at least a portion of a charge ofthermosetting material from said pot means into the mold when said potmeans is at the unloading position, and movable heater means forapplying heat to the thermosetting material in the mold, said means formoving said pot means between the loading and unloading positionsincluding means for moving said heater means from an inactive positiondisposed to one side of the entrance to the mold'to an active positionadjacent to the entrance to the mold simultaneously with movement ofsaid pot means from the unloading position to the loading position toenable said heater means to heat the material in the mold while a chargeof material is loaded into said pot means.

22. An apparatus as set forth in claim 21, further including coolingmeans for maintaining the temperature of thermosetting material in saidpot means below a predetermined temperature when said pot means is atthe loading position.

23. An apparatus as set forth in claim 21 wherein said heater meansincludes a heater block, a heating element supported by said heaterblock, and means for connecting said heater block with'said pot means tomove said heater block relative to the mold upon movement of said potmeans relative to the mold.

24. An apparatus as set forth in claim 23 wherein said heater blockincludes means .for applying pressure to the mold'after movement of saidpot'means from the unloading position'to the loading position.

25. An apparatus as set forth in claim 21 further including preheatermeans for heating'at least a portion of a'strip of the thermosettingmaterial to a temperature below the temperature to which thethermosetting material in the mold is heatedby said heater means, andmeans for loading a preheated portion of the strip of thermosettingmeterial into the mold when the mold is at the loading position. g

26. An apparatus for use in molding thermosetting material, saidapparatus comprising movable pot means for holding a charge of thethermosetting material, said pot means having at least one dischargeopening through which the thermosetting material may pass from said potmeans into amold, means for moving said pot means between a loadingstation at which the discharge opening in said pot means is spaced froman entrance opening to the mold and an unloading station at which thedischarge opening in said pot means is adjacent to the entrance openingto the mold, loader means at said loading station for loading said potmeans with at least a portion'of a charge of the thermosetting'material,means at said unloading station for'forcingat least a portion of achargeof thermosetting material from said-potmeans into the mold, heatermeansfor heating the thermosetting material in the mold to a temperatureabove the setting temperature of the thermosetting material, and coolingmeans at said loading station for maintaining thermosetting materialloaded into said pot means by said loader means at a temperaturebelow-the setting temperature of the thermosetting material duringheating of the thermosetting material in the mold by said heater means.

27. An apparatus as set forth in claim 26 further including preheatermeans for preheating the thermosetting material to atemperature belowits setting temperature prior to loading of the thermosetting materialinto said pot means by said loader means.

28. An apparatus as set forth in claim 27 wherein said means for movingsaid pot means includesmeans for moving said heater means from aninactive position disposed to one side of the entrance to the mold to anactive position adjacent to the entrance to the mold simultaneously withmovement of said pot means from the unloading station to the loadingstation.

29. An apparatus as set forth in claim 1 wherein said means forpressurizing a charge of preheated strip material in said pot meansincludes means for forcing a portion of a charge of preheated materialto flow from said pot means through said discharge opening into the moldand for enabling another portion of the charge to remain in said potmeans,.said apparatus further including means for detecting when theportion of a charge of preheated material remaining in said pot meansafter previous operation of said apparatus and the preheated stripmaterial added to said pot means by said means for loading preheatedstrip material equals a charge of a predetermined magnitude and forinterrupting operation of said means for loading preheated stripmaterial in response to the detecting of a charge of the predeterminedmagnitude in said pot means;

30. An apparatus as set forth in claim 1 wherein said pot means includeswall means defining an open cavity, said means for pressurizing a chargeof preheated material in said pot means including a ram member and meansfor effecting relative movement between said ram member and said potmeans to extrude at least a portion of the charge of preheated stripmaterial from said pot means to the mold, said apparatus'fu-rthe rincluding movable heater means for applying heat to material in the moldand means for moving said heater means between an inactive position inwhich said heater means is disposedto one sideof the mold and an activeposition in which said heater means is disposed between the mold andsaid ram member.

31. An apparatus as set forth in claim 30 further including coolingmeans for maintaining the temperature of the material in said pot meansbelow a predetermined temperature during heating of the material in saidmoldby said heater means.

32. An apparatus for forming molded articles from strip material, saidapparatus comprising preheater means for preheating the strip material,said preheater means including a plurality of flat elongated surfaces,heater means for heating said surfaces, and means for pressing saidsurfaces against opposite sides of a portion of the strip of material toheat the portion of the strip of material engaged by said surfaces, potmeans spaced from said preheater means for receiving a.

charge of preheated strip material, said pot means having at least onedischarge opening through which pre-' heated material may pass from saidpot means into a mold, means for loading at least a portion of a chargeof a preheated strip material from said preheater means into said potmeans, said preheater means further including drive means for movingsaid flat elongated surfaces relative to said means for loading a chargeof preheated material into said pot means to thereby move a heatedportion of the strip material from said preheater means to said meansfor loading a charge of preheated strip material into said pot means,and means for pressurizing a charge of preheated material in said potmeans to force at least a portion of the charge of preheated material toflow from said pot means through said discharge opening into the mold.

33. An apparatus as set forth in claim 32 wherein said preheater meansfurther includes at least one conveyor belt defining one of said flatelongated surfaces, said drive means being operable to move saidconveyor belt along a continuous path with a longitudinally extendingrun of said conveyor belt disposed in abutting engagement with the stripmaterial.

34. An apparatus set forth in claim 32 wherein said preheater meansfurther includes a pair of conveyor belts defining said flat elongatedsurfaces, said drive means being operable to effect movement of each ofsaid conveyor belts along a continuous path having a longitudinallyextending run.

35. An apparatus as set forth in claim 34 wherein said means forpressing said surfaces against opposite sides of a portion of the stripmaterial includes means for urging said'longitudinally extending runs ofsaid conveyor belts toward each other.

36. An apparatus as set forth in claim 21 further including loader meansfor loading at least a portion of a charge of the thermosetting materialinto said pot means at the loading poistion, said means for forcing atleast a portion of a charge of thermosetting material from said potmeans into the mold including means for enabling a portion of the chargeto remain in said pot means, and means for detecting when the portion ofa charge of thermosetting material remaining in said pot means and thethermosetting material added to said pot means by said loader meansequals a charge of a predetermined magnitude and for interruptingoperation of said loader means in response to the detecting of a chargeof the predetermined magnitude in said pot means.

37. An apparatus as set forth in claim 26 wherein said means for forcingat least a portion of a charge of the thermosetting material from saidpot means into the mold includes means for enabling another portion ofthe charge to remain in said pot means, said apparatus further includingmeans for detecting when the portion of a charge of the thermosettingmaterial remaining in said pot means after previous operation of saidapparatus and the thermosetting material added to said pot means by saidloader means equals a charge of a predetermined magnitude and forinterrupting operation of said loader means in response to the detectingof a charge of the predetermined magnitude in said pot means.

38, An apparatus as set forth in claim 26 further includes meansapplying pressure to the mold during the application of heat to thethermosetting material in the mold by said heater means, said means formoving said pot means between said loading and unloading stations alsoincluding means for moving said means for applying pressure from aninactive position disposed to one side of said unloading station to saidunloading station simultaneously with movement of said pot means fromthe unloading station to the loading station.

I! t k i

1. An apparatus for forming molded articles from an elongated strip ofmaterial, said apparatus comprising preheater means for preheating atleast a portion of the elongated strip of material, pot means spacedfrom said preheater for receiving a charge of preheated strip materialfrom said preheater means, said pot means having at least one dischargeopening through which preheated material may pass from said pot meansinto a mold, means for loading at least a portion of a charge ofpreheated strip material from said preheater means into said pot means,and means spaced from said preheater means for pressurizing a charge ofpreheated material in said pot means to force at least a portion of thecharge of preheated material to flow from said pot means through saiddischarge opening into the mold.
 2. An apparatus as set forth in claim 1wherein said preheater means includes means for heating at least aportion of an elongated strip of material, said means for loading acharge of preheated strip material into said pot means including meansfor severing a preheated end portion from the strip of material and forloading the severed end portion into said pot means.
 3. An apparatus asset forth in claim 1 wherein said pot means includes wall means fordefining a cavity for holding a charge of preheated strip meterial, saidmeans for loading a charge of preheated strip material into said potmeans including feed means for positioning a preheated end portion ofthe strip of material across said cavity, piston means cooperable withsaid wall means to sever the preheated end portion from the strip ofmaterial, and means for effecting relative movement between said wallmeans and piston means to sever the preheated end portion from the stripof material.
 4. An apparatus as set forth in claim 1 wherein saidpreheater means includes a purality of flat elongated surfaces, heatermeans for heating said surfaces, and means for pressing said surfacesagainst opposite sides of a portion of the strip of material to heat theportion of the strip of material engaged by said surfaces.
 5. Anapparatus as set forth in claim 4 wherein said preheater means furtherincludes means for moving the heated portion of the strip of materialfrom said preheater means to said means for loading a charge ofpreheated strip material into said pot means.
 6. An apparatus as setforth in claim 5 wherein said means for moving the heated portion of thestrip of material includes drive means for moving said surfaces relativeto said means for loading a charge of preheated strip material into saidpot means.
 7. An apparatus for forming molded articles from stripmaterial, said apparatus comprising preheater means for preheating thestrip material, pot means for receiving a charge of preheated stripmaterial, said pot means having at least one discharge opening throughwhich preheated material may pass from said pot means into a mold, meansfor loading at least a portion of a charge of a preheated strip materialfrom said preheater means into said pot means, means for pressurizing acharge of preheated material in said pot means to force at least aportion of the charge of preheated material to flow from said pot meansthrough said dIscharge opening into the mold, and means for moving saidpot means between a loading station at which the discharge opening insaid pot means is spaced from an entrance opening to the mold and anunloading station at which the discharge opening in said pot means isdisposed adjacent to the entrance opening to the mold, said means forloading a charge of preheated strip material from said preheater meansinto said pot means being located at said loading station, said meansfor pressurizing a charge of strip material in said pot means beinglocated at said unloading station.
 8. An apparatus as set forth in claim7 wherein said pot means includes wall means defining an open cavity,said means for pressurizing a charge of strip material in said pot meansincluding ram means which is disposed in axial alignment with saidcavity when said pot means is at the unloading station and means foreffecting relative movement between said ram means and said pot means toextrude at least a portion of the charge of preheated strip materialfrom said pot means to the mold, said means for moving said pot meansbetween the loading and unloading stations including piston and cylindermeans operatively connected with said pot means and means for effectingoperation of said piston and cylinder means to move said pot meansbetween the loading station in which the open cavity in said pot meansis offset to one side of said ram means and the unloading station atwhich the open cavity in said pot means in disposed in axial alignmentwith said ram means.
 9. An apparatus as set forth in claim 7 furtherincluding movable heater means for applying heat to material in themold, said means for moving said pot means between the loading andunloading stations including means for moving said heater means from aninactive position disposed to one side of the mold to the unloadingstation simultaneously with movement of said pot means from theunloading station to the loading station to enable said heater means toheat material in the mold while a charge of material is loaded into saidpot means at the loading station.
 10. An apparatus as set forth in claim9 further including cooling means for maintaining the temperature ofmaterial in said pot means below a predetermined temperature duringheating of the material in the mold by said heater means.
 11. Anapparatus as set forth in claim 7 further including retainer means forapplying pressure to the mold, said means for moving said pot meansbetween the loading and unloading stations including means for movingsaid retainer means from an inactive position disposed to one side ofthe mold to the unloading station simultaneously with movement of saidpot means from the unloading station to the loading station.
 12. Anapparatus as set forth in claim 11 further including heater means forapplying heat to the material in the mold, said heater means beingmounted on said retainer means for movement therewith from the inactiveposition to the unloading station simultaneously with movement of saidpot means from the unloading station to the loading station to enablesaid heater means to heat material in the mold while said retainer meansapplies pressure to the mold.
 13. An apparatus for use in molding amaterial, said apparatus comprising a mold assembly defining an entranceopening to a mold cavity, said mold assembly including a plurality ofrelatively movable parts, movable pot means for holding a charge of thematerial, said pot means having at least one discharge opening throughwhich the material may pass from said pot means to the entrance openingto the mold cavity, means for moving said pot means between a loadingposition in which the discharge opening is spaced from the entranceopening to the mold cavity and an unloading position in which thedischarge opening is adjacent to the entrance opening to the moldcavity, said pot means being effective at the unloading position toapply pressure to said mold assembly to retain the parts of said Moldassembly against movement relative to each other, means for forcing atleast a portion of a charge of material from said pot means into thecavity in said mold assembly when said pot means is at the unloadingposition, and means for applying pressure to said mold assembly aftermovement of said pot means from the unloading position to the loadingposition to retain the parts of said mold assembly against movementrelative to each other during a setting of material in said moldassembly.
 14. An apparatus as set forth in claim 13 wherein the materialis a thermosetting material and wherein the apparatus further includesmeans for applying heat to the thermosetting material in the mold cavitywhen said pot means is at the loading position.
 15. An apparatus as setforth in claim 14 further including preheater means for preheating acharge of the thermosetting material prior to loading of the charge ofthermosetting material into said pot means.
 16. An apparatus as setforth in claim 15 further including cooling means for maintaining anymaterial remaining in said pot means at a temperature below the settingtemperature of the material when said pot means is at the loadingposition.
 17. An apparatus as set forth in claim 15 wherein saidpreheater means includes strip conveyor means for moving and heating astrip of the thermosetting material, said apparatus further includingmeans for severing an end portion from a heated strip of thethermosetting material and loading the severed end portion into said potmeans when said pot is at the loading position.
 18. An apparatus as setforth in claim 13 wherein said mold assembly includes flash limitingmeans for limiting the formation of flash as the material is forced fromsaid pot means into the mold cavity.
 19. An apparatus as set forth inclaim 13 wherein said pot means and said means for applying pressure tosaid mold assembly are interconnected and define a surface means whichis maintained in continuous engagement with said mold assembly uponmovement of said pot means from the unloading position to the loadingposition.
 20. An apparatus as set forth in claim 13 wherein said potmeans includes a surface which is disposed in pressure engagement withsaid mold assembly when said pot means is in the unloading position,said surface of said pot means defining the discharge opening throughwhich the material passes from said pot means into the mold assembly,said means for applying pressure to said mold assembly including apressure element having a surface which forms a continuation of saidsurface of said pot means, said means for moving said pot means betweensaid loading and unloading positions being effective to move saidsurface of said pressure element into engagement with said mold assemblyand to simultaneously therewith move said surface of said pot means outof engagement with said mold assembly as said pot means moves from saidunloading position to said loading position.
 21. An apparatus for use inmolding thermosetting material, said apparatus comprising movable potmeans for holding a charge of the thermosetting material, said pot meanshaving at least one discharge opening through which the thermosettingmaterial may pass from said pot means into a mold, means for moving saidpot means between a loading position at which the discharge opening insaid pot means is spaced from an entrance opening to the mold and anunloading position at which the discharge opening in said pot means isadjacent to the entrance opening to the mold, means for forcing at leasta portion of a charge of thermosetting material from said pot means intothe mold when said pot means is at the unloading position, and movableheater means for applying heat to the thermosetting material in themold, said means for moving said pot means between the loading andunloading positions including means for moving said heater means from aninactive position disposed to one side of the entrance to the mold to anactive position adjaCent to the entrance to the mold simultaneously withmovement of said pot means from the unloading position to the loadingposition to enable said heater means to heat the material in the moldwhile a charge of material is loaded into said pot means.
 22. Anapparatus as set forth in claim 21, further including cooling means formaintaining the temperature of thermosetting material in said pot meansbelow a predetermined temperature when said pot means is at the loadingposition.
 23. An apparatus as set forth in claim 21 wherein said heatermeans includes a heater block, a heating element supported by saidheater block, and means for connecting said heater block with said potmeans to move said heater block relative to the mold upon movement ofsaid pot means relative to the mold.
 24. An apparatus as set forth inclaim 23 wherein said heater block includes means for applying pressureto the mold after movement of said pot means from the unloading positionto the loading position.
 25. An apparatus as set forth in claim 21further including preheater means for heating at least a portion of astrip of the thermosetting material to a temperature below thetemperature to which the thermosetting material in the mold is heated bysaid heater means, and means for loading a preheated portion of thestrip of thermosetting meterial into the mold when the mold is at theloading position.
 26. An apparatus for use in molding thermosettingmaterial, said apparatus comprising movable pot means for holding acharge of the thermosetting material, said pot means having at least onedischarge opening through which the thermosetting material may pass fromsaid pot means into a mold, means for moving said pot means between aloading station at which the discharge opening in said pot means isspaced from an entrance opening to the mold and an unloading station atwhich the discharge opening in said pot means is adjacent to theentrance opening to the mold, loader means at said loading station forloading said pot means with at least a portion of a charge of thethermosetting material, means at said unloading station for forcing atleast a portion of a charge of thermosetting material from said potmeans into the mold, heater means for heating the thermosetting materialin the mold to a temperature above the setting temperature of thethermosetting material, and cooling means at said loading station formaintaining thermosetting material loaded into said pot means by saidloader means at a temperature below the setting temperature of thethermosetting material during heating of the thermosetting material inthe mold by said heater means.
 27. An apparatus as set forth in claim 26further including preheater means for preheating the thermosettingmaterial to a temperature below its setting temperature prior to loadingof the thermosetting material into said pot means by said loader means.28. An apparatus as set forth in claim 27 wherein said means for movingsaid pot means includes means for moving said heater means from aninactive position disposed to one side of the entrance to the mold to anactive position adjacent to the entrance to the mold simultaneously withmovement of said pot means from the unloading station to the loadingstation.
 29. An apparatus as set forth in claim 1 wherein said means forpressurizing a charge of preheated strip material in said pot meansincludes means for forcing a portion of a charge of preheated materialto flow from said pot means through said discharge opening into the moldand for enabling another portion of the charge to remain in said potmeans, said apparatus further including means for detecting when theportion of a charge of preheated material remaining in said pot meansafter previous operation of said apparatus and the preheated stripmaterial added to said pot means by said means for loading preheatedstrip material equals a charge of a predetermined magnitude and forinterrupting operation of said means for loading preHeated stripmaterial in response to the detecting of a charge of the predeterminedmagnitude in said pot means.
 30. An apparatus as set forth in claim 1wherein said pot means includes wall means defining an open cavity, saidmeans for pressurizing a charge of preheated material in said pot meansincluding a ram member and means for effecting relative movement betweensaid ram member and said pot means to extrude at least a portion of thecharge of preheated strip material from said pot means to the mold, saidapparatus further including movable heater means for applying heat tomaterial in the mold and means for moving said heater means between aninactive position in which said heater means is disposed to one side ofthe mold and an active position in which said heater means is disposedbetween the mold and said ram member.
 31. An apparatus as set forth inclaim 30 further including cooling means for maintaining the temperatureof the material in said pot means below a predetermined temperatureduring heating of the material in said mold by said heater means.
 32. Anapparatus for forming molded articles from strip material, saidapparatus comprising preheater means for preheating the strip material,said preheater means including a plurality of flat elongated surfaces,heater means for heating said surfaces, and means for pressing saidsurfaces against opposite sides of a portion of the strip of material toheat the portion of the strip of material engaged by said surfaces, potmeans spaced from said preheater means for receiving a charge ofpreheated strip material, said pot means having at least one dischargeopening through which preheated material may pass from said pot meansinto a mold, means for loading at least a portion of a charge of apreheated strip material from said preheater means into said pot means,said preheater means further including drive means for moving said flatelongated surfaces relative to said means for loading a charge ofpreheated material into said pot means to thereby move a heated portionof the strip material from said preheater means to said means forloading a charge of preheated strip material into said pot means, andmeans for pressurizing a charge of preheated material in said pot meansto force at least a portion of the charge of preheated material to flowfrom said pot means through said discharge opening into the mold.
 33. Anapparatus as set forth in claim 32 wherein said preheater means furtherincludes at least one conveyor belt defining one of said flat elongatedsurfaces, said drive means being operable to move said conveyor beltalong a continuous path with a longitudinally extending run of saidconveyor belt disposed in abutting engagement with the strip material.34. An apparatus set forth in claim 32 wherein said preheater meansfurther includes a pair of conveyor belts defining said flat elongatedsurfaces, said drive means being operable to effect movement of each ofsaid conveyor belts along a continuous path having a longitudinallyextending run.
 35. An apparatus as set forth in claim 34 wherein saidmeans for pressing said surfaces against opposite sides of a portion ofthe strip material includes means for urging said longitudinallyextending runs of said conveyor belts toward each other.
 36. Anapparatus as set forth in claim 21 further including loader means forloading at least a portion of a charge of the thermosetting materialinto said pot means at the loading poistion, said means for forcing atleast a portion of a charge of thermosetting material from said potmeans into the mold including means for enabling a portion of the chargeto remain in said pot means, and means for detecting when the portion ofa charge of thermosetting material remaining in said pot means and thethermosetting material added to said pot means by said loader meansequals a charge of a predetermined magnitude and for interruptingoperation of said loader means in response to the detecting of a chargeof the predeterminEd magnitude in said pot means.
 37. An apparatus asset forth in claim 26 wherein said means for forcing at least a portionof a charge of the thermosetting material from said pot means into themold includes means for enabling another portion of the charge to remainin said pot means, said apparatus further including means for detectingwhen the portion of a charge of the thermosetting material remaining insaid pot means after previous operation of said apparatus and thethermosetting material added to said pot means by said loader meansequals a charge of a predetermined magnitude and for interruptingoperation of said loader means in response to the detecting of a chargeof the predetermined magnitude in said pot means.
 38. An apparatus asset forth in claim 26 further includes means applying pressure to themold during the application of heat to the thermosetting material in themold by said heater means, said means for moving said pot means betweensaid loading and unloading stations also including means for moving saidmeans for applying pressure from an inactive position disposed to oneside of said unloading station to said unloading station simultaneouslywith movement of said pot means from the unloading station to theloading station.